A touch position sensor is a device that can detect the presence and location of a touch by a finger or by another object, such as a stylus. A touch position sensor, for example, can detect the presence and location of a touch within an area of an external interface of the touch position sensor. In a touch sensitive display application, the touch position sensor enables direct interaction with what is displayed on the screen, rather than indirectly with a mouse or touchpad.
Touch position sensors can be attached to or provided as part of electronic devices, such as computers, personal digital assistants, satellite navigation devices, mobile telephones, portable media players, portable game consoles, public information kiosks, point of sale systems and so on. Touch position sensors may also be used as control panels on appliances.
There are a number of different types of touch position sensors, such as resistive touch screens, surface acoustic wave touch screens, and capacitive touch screens. A capacitive touch screen, for example, may include an insulator, coated with a transparent conductor in a particular pattern. When an object, such as a finger or a stylus, touches or is provided in close proximity to the surface of the screen there is a change in capacitance. This change in capacitance may be sent to a controller for processing to determine the position of the touch.
A radio-frequency identification (RFID) tag can wirelessly exchange data with a RFID reader using radio communication. A RFID tag may include an integrated circuit and an antenna. RFID technologies have been used in a number of identification and tracking applications.